1. Field of Invention
The present invention relates peripheral parts such as a piston, a check valve and a rotary valve for a liquid reservoir in an ink-jet recording system and manufacturing methods of them and also relates an ink-jet recording apparatus having such parts.
2. Brief Description of the Related Arts
FIG. 22 shows a sectional view of an example of conventional piston pumps for liquid ink, consisted of three parts, a cylinder 1, a piston 2 and a check valve 3, assembled into a finished product by inserting the piston 2 into the cylinder 1 after the check valve 3 is engaged in the piston as shown by an arrow in FIG. 23. Character 1a stands for a suction channel for ink, 1b stands for a cylinder space at an ejecting side, 2a stands for an ink channel, 2b stands for a rod portion of the piston, 3a stands for a valve plate and 3b stands for anchor boss respectively.
However, in the manufacturing method of the above-mentioned piston pump an assembling procedure of three parts is inevitable, which requires cost increase in addition to a time for assembling.
Moreover, measures to prevent foreign particles from getting into the piston 2 and the check valve 3 are required so as to keep a good sealing performance of the finished product. Similarly a care to prevent foreign particles from getting into the cylinder 1 is necessary before assembling the cylinder 1 and the piston 2.
In manufacturing rotary valves or slide valves to open/shut or to alter liquid paths, the same manufacturing procedure as the piston pump is employed, where an inner cylinder as a first part, an outer cylinder as a second part and a fastener to prevent the inner cylinder from slipping-out of the outer cylinder, are assembled after forming three parts separately.
This manufacturing procedure, however, also has a drawback requiring an additional assembling step after each part is formed separately, and as a result cost increase as in the case of the previous example.
Some of the finished products consisted of the above-mentioned two parts do not acquire stable rotations or slides due to discrepancies in dimensions or shapes caused by separately manufacturing procedures of the two parts. In some cases liquid leaks out from the finished unit.
In this conventional method, since the additional fastener to prevent the inner cylinder from slipping-out of the outer cylinder is required, number of parts is increased and as a result additional assembling cost is inevitable.
The present invention is carried out in view of the above-mentioned problems and the first objective of the present invention is to supply peripheral parts for ink reservoirs employable for ink-jet recording apparatuses.
The second objective of the present invention is to supply inexpensive parts with less dispersion in their dimension and shape by eliminating assembling procedure of parts followed by forming the above-mentioned parts separately.
The third objective of the present invention is to supply gas-tight and inexpensive parts by employing an elastic material for at least one of the parts.
The present invention is carried out to provide a piston pump, a valve, a pump unit for an ink-jet recording apparatus or an ink-jet recording apparatus according to any one of the following which attain the above-mentioned objectives.
(1) A piston pump comprised of a cylinder, a piston and a valve formed out of mutually insoluble materials each other by an insert molding or a multi-color molding.
(2) A valve comprised of a first part having a cylindrical hole bearing at least one opening for flow path and a second part engaged in the cylindrical hole of the first part capable of rotating freely so as to connect with at least one of the openings for the flow path of the first part, and the first and second parts are formed out of mutually insoluble materials by an insert molding or a two color molding.
(3) A valve comprised of a first part having a cylindrical hole bearing at least two openings for flow paths and a second part, engaged in the cylindrical hole of the first part capable of rotating freely so as to select at least one of the openings for the flow paths of the first part selectively and the first and second parts are formed out of mutually insoluble materials by an insert molding or a two color molding.
(4) A valve comprised of a first part having a cylindrical hole bearing at least one opening for flow path and a second part engaged in the hole of the first part capable of sliding freely so as to connect with at least one of the openings for the flow path of the first part and the first and second parts are formed out of mutually insoluble materials by an insert molding or a two color molding.
(5) A valve comprised of a first part having a cylindrical hole bearing at least two openings for flow paths and a second part engaged in the hole of the first part capable of sliding freely so as to select at least one of the openings for the flow paths of the first part selectively and the first and second parts are formed out of mutually insoluble materials by an insert molding or a two color molding.
(6) Parts for an ink-jet recording apparatus wherein parts are contacted with ink and with other parts, and the parts are formed out of mutually insoluble materials each other by an insert molding or a multi-color molding.
The above-mentioned constitutions according to the present invention, are capable of eliminating assembling procedures by employing insert molded or multi-color molded pumps or valves out of mutually insoluble materials for each other part so as to reduce supervising manhours for manufacturing and so as to provide inexpensive parts with high reliability for an ink-jet recording apparatus.